Stop device for use with well casing



Sept. 1, 1964 J. E. HALL, SR 3,147,029

STOP DEVICE FOR USE WITH WELL. CASING l Filed July 20, 1962 5Sheets-Sheet l I'II Sept. l, 1964 1 E, HALL, SR 3,147,029

STO!J DEVICE FOR USE WITH WELL CASING Filed July 20, 1962 5 Sheets-Sheet2 I INVENTOR. Jesse E. #al .5/1

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Sept. 1, 1964 J. E. HALL, SR

STOP DEVICE FOR USE WITH WELL CASING 3 Sheets-Sheet 3 Filed July 20,1962 INVENToR. deff@ 5 Haq 5f.' BY ,Qj/ J/Qyud Arm NEYS.

United States Patent O 3,147,029 STOP DEVICE FOR USE Wi'IH WELL CASiNG.lesse E. Hall, Sr., Weatherford, Tex., assigner to Trojan, inc.,Panama, Republic of Panama, a Panamanian corporation Filed July 20,1962, Ser. No. 211,185 9 Claims. (Cl. 287-52) This invention relatesgenerally to devices adapted to be mounted on or Within well casings,and refers more particularly to devices operable to provide an abutmenton the wall of the casing operable to limit the movement of appliances,such as scratchers, centralizers, and like tools, along the casing.

One of the main objects of the invention is to provide a stop collarhaving features of construction and operation which permit its use inextremely close tolerance wells, and yet which has great holdingstrength. The device according to the invention has an outer shell whichcan be constructed of light gauge metal and is provided With a thrustactuated locking means which has a construction such that it requiresbut little space between the inside of the shell and casing, thusreducing the over-all thickness of the collar.

Another object of the invention is to provide a stop collar which is soconstructed that it requires no more than its application to the casingto render it eiective as a stop device. In other words, no additionalsteps of driving, wedging pins, turning set screws or othermanipulations are required in order to place it in operating conditionon the casing.

Still another object of the invention is to provide a stop collar whichis capable of being mounted on the casing With speed and facility, andwhich has novel means for drawing it tightly about the casing andmaintaining it in such condition during use.

A further object of the invention is to provide a stop collar of thecharacter described which has a small number of components, isrelatively light in weight and is capable of withstanding rugged use.

Other and further objects of the invention together with features ofnovelty appurtenant thereto will appear in the course ofthe followingdescription.

In the accompanying drawings which form a part of the specification andare to be read in conjunction therewith, and in which like referencenumerals indicate like parts in the various views;

FIG. l is a side elevational view of a preferred device embodying thefeatures of the invention, a portion of the outer shell being brokenaway for purposes of illustration;

FiG. 2 is a plan view of same, part of the shell wall being broken awayand shown in section for purposes of illustration;

FIG. 3 is a side elevational View of a pair of the wedging or lockingstrips disassociated from the shell;

FIG. 4 is an edge-on View of a wedging or locking strip;

FIG. 5 is an enlarged fragmentary elevational View, looking from theinside of the collar at the securing means for joining the ends of theshell;

FlG. 6 is a sectional view taken along line 6 6 of FlG. 5 in thedirection of the arrows;

FIG. 7 is a fragmentary sectional view illustrating the normalunstressed condition of the collar after application of the collar tothe exterior of a casing;

FIG. 8 is a view similar to FIG. 7, but showing the relationship of thecomponents as thrust loads in one direction are applied to the collar;

FIG. 9 is a view similar to FIG. 8, but showing the results of oppositethrust loads on the collar;

ICC

FIG. l0 is a fragmentary plan view of a modified form of the device foruse on the interior of a casing;

FIG. ll is a fragmentary sectional view illustrating the normalunstressed condition of the modiiied form after positioning in thecasing; and

FIG. 12 is a View similar to FIG. l1, but showing the results of theimposition of a thrust load on the device.

Referring to the drawings and initially to the collar shown in FiGS. lthrough 9, the main body of the collar comprises a yband-like shell 20formed from good quality, relatively light gauge metal sheet. The shellis sufficiently flexible that it can be bent to and from the openarcuate configuration shown in broken lines in FIG. 2, to the closedcircular configuration shown in solid lines.

The shell 20 is formed with inturned upper and lower flanges 2l., 22,respectively (FIG. 7) and with two inwardly depressed parallel ribs 23,each of which defines upper and lower annular shoulders 23a, 231) on theinside Wall of the shell. These shoulders are preferably of long radiuswhereby to provide a gradual wedging surface7 the reasons for which willlater become more apparent.

Disposed on the inside of the shell and extending circumferentiallythereof is a pair of similar wedging or locking strips 24, each of whichis associated with and overlies a rib 23 of the shell. These strips arepreferably formed from high quality hardened spring steel havingsuiiicient fiexibility as to be deformable with the shell as previouslydescribed.

Each strip 24 has its opposed margins formed into a scallopedconfiguration providing alternating inwardly and outwardly directedprojections 24a and 24h, respectively, Which lie on opposite sides ofthe major plane of the strip. As is best seen in FIG. 7, the scallopsare such that the maximum depth occurs at the extreme edge of the strip.The central portion 24C of the strip is iiat and of substantially thesame width as the associatedV inner face of the rib 23, and thescalloped projections 24a, 24!) iiare inwardly and outwardly therefromwith the outwardly directed projections 24b overlapping the shoulders23a, 23h. The inwardly directed projections 24a thus provide sharp edgedspaced arcuate segments which lie adjacent and contact the casing.

Each wedging strip 24, rather than being secured to the shell 2i), ispreferably seated therein under flexural stress. This is accomplished byinitially forming the strip in such fashion that it must be resilientlyexed to bring it within the shell, after which it is released. Thetendency of the strip to again return to a straighter configurationcauses it to center itself on the associated rib and to maintain it inoperative condition within the shell.

The opposite ends of the respective wedging strips 24 lie adjacent endabutments 26, 27 which serve to prevent circumferential shifting of thestrips in the shell. The abutments are formed as the registering endedges of plies of metal sheet 28, 29, spot welded to the collar ribs 23on the inside thereof as at 30. The plies 28, 29 are extended beyond theend of the shell to form inter-engaging loop-like portions 31 whichdefine together a central thin slot 32 through which can be inserted thepintle elements 33, 34 to connect the ends of the shell together. Itwill be noted that the plies 28, 29 are cut to provide shoulders 35which overlie the ends of iianges 21, 22. This assists materially inmanufacture, providing a means of accurately positioning the plate-likeelements formed of fthe plies 28, 29 on the Shell during the weldingoperation.

The pintle elements 33, 34 are right triangular pieces adapted to beinserted from opposite ends of the slot 32 and firmly driven in opposeddirections to draw or constrict the collar and wedging strips about thecasing with the projections on the latter in firm initial contact withthe casing. The diagonal abutting surfaces of the pintle elements serveto effect a constricting force on the shell, the opposite edges of thepintle elements benig separated further and further as one elementproceeds longitudinally of the other, and thus drawing the loops 31relatively together.

In operation, the device as thus far described is prepared forinstallation by removing the pintle elements 33, 34, if present, andopening up the collar sufllciently (see FIG. 2) to permit it to be movedinto encircling position on a casing. Thereupon the ends are broughttogether to conform the collar to the casing and to inter-engage theloop portions 31 sufficiently to permit insertion of the piutleelements, as previously described. The pintle elements are driven homesutliciently as to insure that the collar has a rm grip on the casingthrough the interengagement therewith of the projections 24a on thewedging strips.

The ordinary function of stop collars and similar devices on the casingis to provide a limiting abutment operable to define fthe limits ofmovement to be provided certain other appliances, such as scratchers andcentralizers. When such appliances engage or are engaged by the collar,a thrust is applied to the collar tending to shift the collar on thecasing.

As shown in FIG. 8, if the thrust force is imposed on the lower ilange22 of the shell 20, the shell tends to be shifted upwardly on thecasing. This, however, causes the shoulders 23a to engage the outwardlyprojecting scallops 24h on the upper edges of the wedging strips andapply an inward force causing the associated inwardly projectingscallops 24b to bite into the casing. The large number of scallopsforced into engagement with the casing insures of relatively uniforminward pressure and gripping around the casing. The greater the force,the deeper the tendency of the scallops to bite into the casing, withthe result that the collar holds firm under very heavy loads.

FIG. 9 illustrates the result when the thrust is imposed against the topflange 21 of the collar. The situation is the reverse of that justdescribed, the lower shoulders 23b now acting on the scallopedprojections at the lower edges of the strips.

While 'the shell is put under substantial circumferential tension underhigh thrust loads, the special end connection provided by the diagonallyabutting pintle elements provides a high degree of safety againstaccidental disconnection of the ends. The angle of abutment issuiliciently shallow that the resultant forces tending to cause thepintle elements to slip are insufficient to overcome the high frictionalresistance to slippage.

The curved scalloped character of the casing engaging projections 24aassists in preventing penetration to the point where the collar couldslip up over the strips. The greater the depth to which the edges of thescallops penetrate, the more the surface area of the scallop broughtinto contact with the casing, with the result that there is aninhibiting tendency once the penetration has been effected.

As shown in FIGS. through 12, inclusive, the principles of the inventionare equally applicable to stop devices for mounting on the interiorrather than the exterior of a casing. As shown in FIG. l0, in this casethe collar is formed so that the wedging strips 124 are located on theexterior of the collar. The ribs 123 and flanges 121, 122 are directedoutwardly rather than inwardly. In order to facilitate the circularconformation the upper and lower flanges 121, 122 are segmented, as isbest seen in FIG. 10. The ribs are provided, as in the precedingembodiment, with upper and lower shoulders 123a, 123b, respectively. Thewedging strips 124 are constructed much the same as those in thepreceding embodiment, having the alternating projections 124e and 124i)along the opposed marginal edges.

As shown in FIG. l2, thrust against the end flange of the collar 120, inthis case the lower end flange 122, will cause inward compression of thescalloped projections and cause them to bite into the casing to inhibitmovement. Obviously, thrust in the opposite direction works in thereverse direction, causing the lower shoulders 123b to operate againstthe scallops at the lower edge of the strip.

From the foregoing it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forthtogether with other advantages which are obvious and which are inherentto the structure.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinatons. This is contemplated by and is within the scope of theclaims.

As many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying drawings is to beinterpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. In a stop collar for use with a well casing, the combination of aflexible interrupted circular band having confronting end portions andat least one circumferential rib formed on a face thereof to providespaced parallel annular shoulders, a flexible wedging strip disposedadjacent said face and extending substantially from one end of said bandto the other, said wedging strip having a central portion overlying saidrib along the length thereof, the marginal edges of said strip onopposite sides of said central portion being scalloped to providealternately directed projections along said marginal edges directedtoward aud away from said face, those Projections directed toward saidface adapted to cooperate with their respectively adjacent shouldersupon relative axial movement between said band and strip and apply aforce tending to move the strip radially away from said face, andreleasable means for connecting said ends of said band.

2. In a stop collar for mounting on a well casing, the combination of aflexible interrupted circular band having confronting end portions andat least one circumferentially extending rib formed on the inside facethereof and presenting spaced parallel annular shoulders on the insideface of the band, a flexible wedging strip extending substantially fromone end of the band to the other and having a central portion overlyingsaid rib along the length thereof, the marginal edges of said strip onopposite sides of said central portion being scalloped to providealternately directed projections along said marginal edges directedtoward and away from said face, those projections directed toward saidface adapted to cooperate with said shoulders upon relative axialmovement between the band and strip, and releasable means connectingsaid ends of said band.

3. A collar as in claim 1 wherein said face comprises the outside faceof the band.

4. A collar as in claim l wherein said face comprises the inside face ofsaid band.

5. In a stop collar for use with a well casing, the combination of aflexible interrupted circular band having confronting end portions and apair of axially spaced circumferentially extending annular shouldersformed on a face thereof, a flexible wedging strip disposed adjacentsaid face and extending substantially from one end of said band to theother and having a width such that its marginal edges extend past therespective shoulders, said edges being scalloped to provide projectionsdirected alternately toward and away from said face, those projectionsdirected toward said face adapted to cooperate with their respectivelyadjacent shoulders upon relative axial movement between said band andstrip and apply force tending to move the strip radially away from saidface, and releasable means connecting said ends of said band.

6. A stop collar as in claim 5 wherein said strip is resiliently biasedtoward said face.

7. A stop collar as in claim 5 wherein said face comprises the insideface.

8. A stop collar as in claim 5 wherein said face comprises the outsideface.

9. A stop collar as in claim 5 wherein said releasable 5 means comprisesmembers connected with the respective ends of the band, said membershaving inter-engaging finger portions apertured to form a continuouspassageway parallel with the axis of said band, and a split elongatepintle extending into said passage, the pintle being put 10 diagonallyto the long axis thereof whereby to provide confronting edge surfaces atan angle with said long axis.

References Cited in the file of this patent UNITED STATES PATENTS SparksAug. 11, 1896 Bigger Oct. 12, 1915 King Feb. 26, 1946 Gist Apr. 29, 1952Jones Feb. 10, 1953 Stade Apr. 13, 1954 Bjorklund May 12, 1959 Good June21, 1960 Brown Apr. 3, 1962

1. IN A STOP COLLAR FOR USE WITH A WELL CASING, THE COMBINATION OF AFLEXIBLE INTERRUPTED CIRCULAR BAND HAVING CONFRONTING END PORTIONS ANDAT LEAST ONE CIRCUMFERENTIAL RIB FORMED ON A FACE THEREOF TO PROVIDESPACED PARALLEL ANNULAR SHOULDERS, A FLEXIBLE WEDGING STRIP DISPOSEDADJACENT SAID FACE AND EXTENDING SUBSTANTIALLY FROM ONE END OF SAID BANDTO THE OTHER, SAID WEDGING STRIP HAVING A CENTRAL PORTION OVERLYING SAIDRIB ALONG THE LENGTH THEREOF, THE MARGINAL EDGES OF SAID STRIP ONOPPOSITE SIDES OF SAID CENTRAL PORTION BEING SCALLOPED TO PROVIDEALTERNATELY DIRECTED PROJECTIONS ALONG SAID MARGINAL EDGES DIRECTEDTOWARD AND AWAY FROM SAID FACE, THOSE PROJECTIONS DIRECTED TOWARD SAIDFACE ADAPTED TO COOPERATE WITH THEIR RESPECTIVELY ADJACENT SHOULDERSUPON RELATIVE AXIAL MOVEMENT BETWEEN SAID BAND AND STRIP AND APPLY AFORCE TENDING TO MOVE THE STRIP RADIALLY AWAY FROM SAID FACE, ANDRELEASABLE MEANS FOR CONNECTING SAID ENDS OF SAID BAND.